Prealgebra, Chapter 4 Equations: 4.2 The Addition/Subtraction Principle of Equality Definitions:
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Linear equation – An equation that is made of polynomials or monomials
that are at most degree “1”
Objective 1: Determine whether a given equation is linear
o 2x – 8 = 14
o 7y = 21
o
Objective 2: Solve linear equations in one variable using the addition/subtraction
principle of equality
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The addition/subtraction principle of equality
o The same amount can be added to or subtracted from both sides of
an equation without affecting its solution
o x – 8 = -15
o 14 = m + 5
Objective 3: Solve equations with variable on both sides of the equals sign
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First, distribute to get rid of any parenthesis
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Then, combine like terms on each side of the equals sign
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Finally, put all of your variable terms on one side of the equals sign and all
you number terms on the opposite side of the equals sign with the
addition/subtraction principle of equality
o 7x – 9 = 6x – 11
o y – (2y + 9) = 6(y – 2) – 8y
Resource: Carson, T. (2009 ). Prealgebra – 3rd ed..